there are a few different manufactures out there that make protective screen covers for the psp. as for the best on, i couldn't tell you. i went to "game" and got mine from there.
there is a thread in this section about this subject. click "
HERE" to view it and see what was said in the thread. i know a few members recommend different protectors. at the end of the day, it's up to you what you go for.